Fluid valve and mixing assembly

ABSTRACT

A fluid valve and mixing assembly comprising a valve housing having a fluid nozzle with an inlet end and an outlet end. A first inner conduit is connected to the nozzle inlet end for supplying a first fluid under pressure thereto. A piston is mounted in a sleeve in the housing beyond the nozzle and is provided with a sealing means at one end thereof. Spring means normally bias the piston against the outlet end of the nozzle so that the sealing means normally closes the outlet end. A second outer conduit concentric with the first conduit is connected to the entrance end of the valve housing for supplying a second fluid under pressure thereto. A first fluid passageway is formed between the nozzle and the valve housing to permit the second fluid to initially pass through the valve housing past the nozzle. A second fluid passage is provided around the outside of the piston which is normally closed but which is opened when the piston moves away from the nozzle with the flow of the second fluid. The movement of the piston away opens the nozzle outlet and permits the first fluid to exit from the nozzle and mix with the second fluid whereby the mixture of the fluids then passes through the second passageway to be discharged through the exit end of the valve housing. The first fluid passing through the nozzle has a greater fluid pressure than that of the second fluid passing around the nozzle so that the first fluid upon leaving the nozzle outlet end flows outwardly in the valve housing to mix with the second fluid passing around the outside of the nozzle to facilitate mixing the two fluids. When the flow of the second fluid is cut off, the spring loaded piston returns to its closed position forcing the seal means against the outlet end of the nozzle to cause all fluid flow to cease.

United States Patent im 4 Freeman et a].

Oct. 9, 1973 FLUID VALVE AND MIXING ASSEMBLY Inventors: Craig Freeman, Van Nuys; Robert D. Hetherington, Sunland, both of Calif.

[73] Assignee: Ransburg Electra-Coating Corp.,

7 Indianapolis, Ind. [22] Filed: Mar. 21, 1972 Appl. No.: 236,740

9/l959 Tacchi 137/111 X Primary Examiner-Martin P. Schwadron Attorney-Merrill N. Johnson et al.

[57] ABSTRACT A fluid valve and mixing assembly comprising a valve housing having a fluid nozzle with an inlet end'and an outlet end. A first inner conduit is connected to the nozzle inlet end for supplying a first fluid under pressure thereto. A piston is mounted in a sleeve in the housing beyond the nozzle and is provided with a sealing means at one end thereof. Spring means normally bias the piston against the outlet end of the nozzle so that the sealing means normally closes the outlet end. A second outer conduit concentric with the first conduit is connected to the entrance end of the valve housing for supplying a second fluid under pressure thereto. A first fluid passageway is formed between the nozzle and the valve housing to permit the second fluid to initially pass through the valve housing past the nozzle. A second fluid passage is provided around the outside of the piston which is normally closed but which is opened when the piston moves away from the nozzle with the flow of the second fluid. The movement of the piston away opens the nozzle outlet and permits the first fluid to exit from the nozzle and mix with the second fluid whereby the mixture of the fluids then passes through the second passageway to be discharged through the exit end of the valve housing. The first fluid passing through the nozzle has a greater fluid pressure than that of the second fluid passing around the nozzle so that the first fluid upon leaving the nozzle outlet end flows outwardly in the valve housing to mix with the second fluid passing around the outside of the nozzle to facilitate mixing the two fluids. When the flow of the second fluid is cut off, the spring loaded piston returns to its closed position forcing the seal means against the outlet end of the nozzle to cause all fluid flow to cease.

9 Claims, 6 Drawing Figures 1 FLUID VALVE AND MIXING ASSEMBLY BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to a fluid valve and mixing assembly adapted to dispense and mix at least two different fluids and more particularly to such an assembly employing a spring loaded piston movable in a guide sleeve to open and close a fluid nozzle to facilitate the mixing of a stream of air and a catalyst.

2. Description of the Prior Art Various fluid valve and mixing devices have previously been known for mixing a plurality of fluids prior to their discharge through a suitable fluid dispenser such as a spray gun. More specifically, in connection with the manufacture of plastics of the polyester and epoxy resin type which require mixing a catalyzing agent with a resinous material, it is desirable to first thoroughly mix the catalyst with a source of air under pressure. Since the catalyst used in this type of application is volatile and combustible or flammable, care should be taken in the handling of the catalyst. It is therefore desirable to keep the amount of air mixed with the catalyst at a minimum so that the amount of catalyst fumes is minimized.

Several of the known mixing devices have not satisfactorily provided means for mixing the air and the catalyst employing a minimum amount of air pressure. Other known devices have not provided adequate means for handling the volatile catalyst material. Still other known devices have not functioned smoothly and efficiently in mixing the air and the catalyst.

SUMMARY OF THE INVENTION Among the features of the present invention is to avoid the disadvantages of the known fluid mixing devices enumerated above. Another feature of the present invention is to provide a fluid valve and mixing assembly which controls and mixes at least two different fluids such as a catalyst and air. A further feature of the invention is to provide a fluid valve and mixing assembly which appropriately mixes two fluids such as catalyst and air while requiringa minimum amount of air pressure. Still another feature of the present invention is to provide a fluid valve and mixing assembly employing a spring biased piston movable in a ported guide sleeve for opening and closing a nozzle in response to the flow of fluid through the assembly. Still another feature of the invention is to provide an assembly having means for handling a volatile and combustible or flammable fluid such as a catalyst.

The present invention includes a fluid valve and mixing assembly comprising a valve housing having a central chamber with an entrance end and an exit end. A fluid nozzle having an inlet end and an outlet end is mounted in the chamber with a first inner conduit connected to the inlet end for supplying a first fluid under pressure to the nozzle. A sleeve is mounted in the chamber beyond the nozzle and is provided with a plurality of portsin the end away from the nozzle. The valve housing is comprised of two sections threadably connected together whereby the end of the second section abuts against at least a portion of the sleeve to retain the sleeve in position in the chamber.

A movable means such as a piston having sealing means mounted in one end is movable in the sleeve.

Means bias the piston against the outlet end or orifice of the nozzle so that the sealing means normally closes the orifice.

A second outer conduit concentric with the first conduit is connected to the housing. entrance end for supplying a second fluid under pressure to the chamber. A first fluid passageway is formed between the nozzle and the chamber to permit the second fluid to initially pass through the chamber beyond said nozzle while a second fluid passageway is formed around the outside of the piston. The second passageway is normally closed but is opened when the piston is moved away from the nozzle orifice by the flow of the second fluid. The movement of the piston away from the nozzle orifice permits the first fluid to exit from the nozzle orifice and mix with the second fluid so thatthe mixture of fluids then passes through the second passageway to be discharged through the exit end of the housing.

The first fluid passing through the nozzle is supplied at a pressure greater than that of the second fluid flowing around the nozzle so that the first fluid upon being discharged from the nozzle orifice is caused to flow outwardly and mix with the second fluid.

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will become apparent by reference to the more detailed descripton of the invention and the accompanying drawings which follow wherein:

FIG. 1 is a perspective view of a fluid valve and mixing device according to the present invention positioned for connection to a concentric double hose assembly and a suitable spray gun;

FIG. 2 is a sectional view taken along line 22 of FIG. 1 illustrating the fluid valve and mixing asssembly according to the present invention in detail;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along line 4--4 of FIG. 2;

FIG. 5 is a sectional side elevational view of a portion of a fluid valve and mixing device according to the present invention showing the piston positioned in the ported guide sleeve against the nozzle; and

FIG. 6 is a sectional view taken along line 66 of FIG. 5;

DESCRIPTION OF THE INVENTION Referring to the drawings, there is shown in FIG. 1 a fluid valve and mixing assembly 10 adapted to be connected at its entrance end 30 to a means for supplying fluids thereto such as double hose assembly 11 and at its exit end 39 to a suitable spray gun 12. The double hose assembly 11 is comprised of an inner conduit 13, preferably of plastic, and a concentric outer conduit 14. A coiled spring 15 may be positioned around the exterior of the outer conduit 14 to provide a more controlled flexing of the conduit as well as to afford protection to the conduit. The end of outer conduit 14 also is provided with a suitable internally threaded cap 16 for connection to the entrance end 30 of the fluid valve and mixing assembly 10. In one use of the device of the present invention, the inner conduit 13 isemployed to supply a catalyst such as methyl ethyl ketone peroxide under pressure to a fluid nozzle 40 (shown in FIG. 2) of the fluid mixing assembly while the outer conduit 14 is utilized to supply compressed air to the fluid valve and mixing assembly as will be explained more fully hereinafter. The outer conduit 14 functions as an additional safeguard to minimize leakage in the event the inner conduit 13 should fail such as by breaking or rupturing.

The spray gun 10 may be of any suitable type such as that shown and described in Johnson et al. US. Pat. No. 3,330,484 issued July II, 1967. Spray guns of this type are particularly adapted to spray a variety of thermosetting plastics, catalyzed glues, gel coats, liquid foams, etc. As shown in FIG. 1, the spray gun is provided with a suitable internally threaded inlet connection or bore 17 for connection to the exit end of the fluid valve mixing assembly 10. If the device of the present invention is used with a thermosetting plastic such as polyester resin, the air and catalyst mixture from the fluid valve and mixing assembly 10 is mixed with the resin within spray gun 12 prior to ejection therefrom.

Referring now to FIG. 2 for a more detailed description of the invention, there is shown the fluid valve and mixing assembly 10 comprising a valve housing or body 20 having a first section 21 and a second section 22 threadably connected together. Suitable sealing means such as O-ring 28 seal is provided between the two sections 21 and 22 to minimize leakage of fluids. Both the entrance end 30 and the exit end 39 of the valve housing 20 are provided with suitable threaded connecting portions 23 and 24 respectively.

The valve housing 20 is provided with a central chamber 35 having an entrance end 30 and exit end 39. The entrance end 30 has a portion 26 which tapers inwardly to a smaller cylindrical passage 31 which then communicates with the central chamber 25. The chamber has a cylindrical first portion 32 and an enlarged cylindrical second portion 33 which define a shoulder 34 therebetween. Portions 32 and 33 are both contained in the first section 21 of the valve housing 20. The remainder of the chamber 25 is formed in the second section 22 of the valve housing 20 and is comprised of another intermediate portion 35 of slightly less diameter than cylindrical second portion 33, inwardly extending shoulder 36 and end portion 37. End portion 37 of the chamber 25 is provided with an end cavity or recess 38 which communicates with the central passageway 27 in exit end 39.

A fluid nozzle 40 is mounted adjacent the entrance end of chamber 25 and is provided with an inlet end 41 and an outlet end 42. Fluid nozzle 40 is comprised of a main body member 43, washer 45 and nut 46, as shown in FIG. 2.

The main nozzle body member 43 is comprised of a cylindrical portion 47 having threads 48 at one end and a plurality of webs 49 extending outwardly from the opposite end. The webs 49 define a plurality of spaced, generally semicircular shaped openings or passageways 50 (as shown in FIG. 3) around the periphery of cylindrical second portion 33 of chamber 25. The outer end of each of the webs 49 abuts against the shoulder 34 between portions 32 and 33 of the chamber 25.

Main body member 43 of fluid nozzle 40 is provided with a chamber 51 at its inlet end which tapers down to a central passageway 52 which in turn communicates with an orifice 53 from which fluid is ejected. Orifice 53 is contained in a tip 54 protruding from the end of the main body member 43 of fluid nozzle 40.

The inner conduit 13 of the double hose assembly 11 extends through the inlet end 41 of the nozzle 40 and terminates in the chamber 51 of the main body member 43 of the nozzle. As shown in FIG. 2, the nut 46 retains the sleeve 44 and the washer 45 against the end of main body member 43 to facilitate locking the inner conduit 13 in position inside of the fluid nozzle 40. The inner conduit 13 supplies a first fluid under pressure, such as a catalyst, to the inside of the fluid nozzle 40 without initially being dispensed to any other part of the fluid valve and mixing assembly 10.

The fluid nozzle 40 is retained in position in the chamber 25 by a cylindrical sleeve which abuts against the outer edges of the webs 49 to position the webs against shoulder 34. Sleeve 60 is provided with an inwardly extending shoulder 61 generally intermediate its length which abuts against the end of the second section 22 of the valve housing 10. When section 22 is threadably connected to the first section 21, the end of section 22 abuts against the shoulder 61 to retain the sleeve 60 and consequently the fluid nozzle 40 in position in the chamber 25. As shown in FIGS. 2, 5 and 6, sleeve 60 is provided at its end away from the fluid nozzle 40 with at least two ports or slots 62 preferably spaced about 180 degrees apart.

A piston is mounted in the sleeve 60 and is movable lengthwise thereof. Sleeve 60 has an inwardly extending lip 63 which limits the movement of piston 65 in the direction of fluid flow. As shown in FIG. 5, piston 65 is provided with a generally rectangular main body portion 66 and a circular end portion 67. The four corners of the rectangular main body portion 66 are rounded to conform with the contour of the inside chamber of sleeve 60. The flattened sides of the rectangular main body portion 66 between each of the rounded corners 68 form a plurality of passageways 69, in this instance four as shown in FIG. 4, between the rectangular portion 66 and the inside of the sleeve 60. The circular end portion 67 forms a seal with the inside of the sleeve 66 all the way around the interior of the sleeve.

Referring again to FIG. 2, the end of piston 65 adjacent the fluid nozzle 40 is provided with a cavity or recess 70 for receiving a suitable sealing member 71 therein for the closing orifice 53. Sealing member 71, which may be of any suitable material such as rubber, forms a face seal for normally closing the orifice 53 of the fluid nozzle 40. Piston 65 is normally biased towards the nozzle 40 by means of a suitable bias means 73 such as a coil spring whereby the sealing member 71 normally seals orifice 53 when no fluids are flowing through the fluid valve and mixing assembly 10. One end of spring 73 abuts against the shoulder 74 on circular end portion 67 of the piston 65 while the other end of spring 73 is received in the cavity 38 of the second section 22 of the valve 20.

In operation of the fluid valve and mixing assembly 10 of the present invention, a first fluid such as a catalyst is supplied under pressure to the inner conduit 13 of the double hose assembly 11 while a second fluid under pressure, such as air, is supplied to the entrance end 30 of the chamber 25 of the housing by the outer conduit 14. Normally the piston 65 is in the position shown in FIG. 5 whereby the sealing means 71 closes the orifice 53 of the fluid nozzle 40 so that any fluid entering into the interior of the nozzle 40 through conduit 13 is prohibited from exiting through the orifice 53. A

second fluid under pressure is supplied to the chamber 25 through outer conduit 14. The second fluid, which may be air under pressure, travels around the body of fluid nozzle 40 on the outside of chamber 25, through the passageways 50 formed between the webs 49 of the fluid'nozzle 40 and then through the passageways 69 formed between the rectangular portion 66 0f the piston 65 and the inside of the cylindrical-sleeve 60 as shown by arrows 57. At this point the second fluid contacts the inner end of the circular end portion 67 of the piston 65, thus moving the piston towards the exit end 39 of chamber 25. As the piston 65 moves in the direction of fluid flow, the sealing circular end portion 67 travels beyond the point where the ports or slots 62 of the sleeve are positioned. As soon as this happens, the fluid passing around the outside of the rectangular portion 66 of the piston, exits through the ports 62 into the end portion 37 of chamber 25 and then out through the central passageway 27 of the exit end 39.

Moreover, as the piston 65 moves toward the exit end 39 of chamber 25, the orifice 53 of the fluid nozzle 40 is opened to permit the first fluid or catalyst supplied through inner conduit 13 to exit through the orifice 53 into the interior of the sleeve 60 as shown by arrows 58. If the first fluid or catalyst is supplied at a pressure greater than the second fluid flowing around the outside of the nozzle, the first fluid will flow outwardly to the periphery of the inside of the sleeve 60 and mix with the second fluid. From this point, the mixture is moved through the passageways 69, ports 62 and the exit end 39 of the assembly 10. It is important in the operation of the device of the present invention that the first fluid supplied to the inside of the nozzle 40 be at a greater pressure than the second fluid supplied to the chamber 25. When the flow of the second fluid is stopped, the energy stored in the spring 73 due to the initial displacement of the piston 65 is released and the piston 65 returns to its normally closed position with the sealing member 71 biased against the orifice 53 of the nozzle 40, thus terminating fluid flow from the orifice.

The advantages of the present invention are believed readily apparent from the above description. The fluid valve and mixing assembly permits two fluids, such as air and a catalyst, to be maintained separately and subsequently mixed for further usage. The spring loaded piston 65 provides a convenient means for preventing fluid flow through the assembly 10 until a second fluid under pressure is supplied to the chamber 25 of the valve and mixing assembly 10. Moreover, the means of the present invention provides a convenient means for mixing two separate fluids. It is simply necessary to provide the first fluid supplied to the interior of the nozzle at a greater pressure than the second fluid supplied to the chamber so that upon opening the orifree 53 of the fluid nozzle 40, the first fluid flows outwardly to be mixed with the second fluid passing through the chamber of the means. The mixing of the two fluids thus can be accomplished with a minimum of air pressure.

It should be appreciated that the concepts of the present invention are applicable to spraying of most plural component materials including, but not limited .to, polyester resins, epoxy resins, urethane resins, silicone rubber and the like. Generally, the plural component material is converted, at ambient atmospheric temperature, from a liquid phase to a solid phase by the addition of an appropriate catalyst or curing agent. Polyester resins may be cured by the addition of a peroxide catalyst and a naphthenate or aniline promotor. Epoxies may be cured by the addition of a suitable amine or anhydride curing agent thereto. Urethanes may be obtained by the addition of a suitable isocyanate ester to a polyester resin. Silicone rubber may be obtained by the addition of a suitable tin soap to a silicone elastomer.

Although the present invention has been illustrated and described with reference to a specific embodiment,-

it will be understood that various modifications may be made by persons skilled in the art without departing from the spirit of the invention which is defined solely by the appended claims.

We claim:

1. A two-fluid valve and mixing assembly comprising a housing having an entrance opening and an exit opening and a central chamber therebetween;

a fluid nozzle carried in the central chamber and forming first and second conduits with the housing in the central chamber, each conduit having its input at the end nearest the entrance end of the housing and its outlet nearest the exit end of the housing;

a cylinder formed in the central chamber of the housing adjacent the outlets of the first and second conduits; i

a piston movably carried in the cylinder adjacent the outlets of the first and second conduits, said piston forming with the cylinder a combined passageway between the outlets of the first and second conduits and the exit opening of the housing, having sealing means at one end adapted to close the outlet of the first conduit, and having at its other end a portion cooperating with the cylinder to close the combined passageway;

means to bias the piston and its sealing means against the outlet of the first conduit to seal the first conduit and simultaneously block the combined passageway formed by the piston and cylinder, the outlet of the second conduit being open to the cylinder when the piston is biased against the outlet of the first conduit;

first connecting means at the entrance opening of the housing to connect the first conduit of the fluid nozzle with a source of a first fluid under pressure, and second connecting means at the entrance end of the housing to connect the second conduit with a source of a second fluid, under pressure, whereby supply of the second fluid under pressure through the outlet of the second conduit moves the piston within the cylinder, opening the outlet of the first conduit and opening the combined passageway so that the first fluid is free to mix with the second fluid and to pass through the exit opening of the housing.

2. A fluid valve and mixing assembly according to claim 1 wherein the cylinder is formed by a sleeve in the central chamber for guiding the piston.

3. A fluid valve and mixing assembly according to claim 2 wherein the sleeve has a port on the end away from the fluid nozzle and the piston has a portion of its periphery of lesser dimension than the sleeve to form with the sleeve the combined passageway whereby movement of the piston away from the fluid nozzle opens the port to permit the mixture of fluids to pass therethrough around the piston.

4. A fluid valve and mixing assembly according to claim 3 wherein the sleeve is cylindrical and has a plurality of ports and the piston has a portion having a plurality of flat sides to form the combined passageway with a plurality of passageways.

5. A fluid valve and mixing assembly according to claim 1 wherein the inlet of the fluid nozzle and the entrance end of the housing are adapted for connection to concentric inside and outside conduits attached to the valve housing at the entrance end, the inlet of the fluid nozzle retaining the inside conduit and the outside conduit being connected to the entrance end to supply a second fluid for passage around the fluid nozzle.

6. A fluid valve and mixing assembly according to claim 1 wherein the fluid nozzle includes a portion at the outlet of the second conduit having a plurality of webs extending outwardly therefrom, the webs defining with the fluid nozzle and the housing, a plurality of outlets to permit said second fluid to flow past the fluid nozzle.

7. A fluid valve and mixing assembly comprising a valve housing having a central chamber with an entrance end and an exit end,

a fluid nozzle mounted in the central chamber having an inlet end and an outlet end,

a first inner conduit adapted to be connected to the fluid nozzle inlet end for supplying a first fluid under pressure to the outlet end of the fluid nozzle,

a sleeve mounted in the chamber beyond the fluid nozzle, the sleeve having a plurality of ports in the end away from the nozzle,

a piston mounted in the sleeve and movable lengthwise thereof,

sealing means mounted at one end of the piston,

spring means biasing the piston against the outlet end of the fluid nozzle so that the seal means normally closes the outlet end of the fluid nozzle,

a second outer conduit concentric with the first conduit and adapted to be connected to the housing entrance end for supplying a second fluid under pressure to the central chamber,

a fluid outlet formed between the fluid nozzle and the sleeve to permit the second fluid to initially pass into the central chamber past the fluid nozzle, and

a second fluid passageway formed by the outside of the piston and the sleeve which is normally closed but which is opened when the piston is moved away from the fluid nozzle by the flow of the second fluid, the movement of said piston away from the fluid nozzle also permitting the first fluid to exit from the fluid nozzle and mix with the second fluid whereby the mixture of the fluids passes through the second passageway and is discharged through the exit end of the housing.

8. A fluid valve and mixing assembly according to claim 7 wherein the sleeve has a port on the end away from the fluid nozzle and the piston has a portion of its periphery of lesser dimension than the sleeve which forms part of the second fluid passageway whereby movement of the piston away from the fluid nozzle opens the port to permit the mixture of fluids to pass therethrough around the end of the piston.

9. A fluid valve and mixing assembly according to claim 7 wherein the housing has a first section and a second section connected together, the end of the sec ond section abutting against at least a portion of the sleeve to retain the sleeve in position in the central chamber. 

1. A two-fluid valve and mixing assembly comprising a housing having an entrance opening and an exit opening and a central chamber therebetween; a fluid nozzle carried in the central chamber and forming first and second conduits with the housing in the central chamber, each conduit having its input at the end nearest the entrance end of the housing and its outlet nearest the exit end of the housing; a cylinder formed in the central chamber of the housing adjacent the outlets of the first and second conduits; a piston movably carried in the cylinder adjacent the outlets of the first and second conduits, said piston forming with the cylinder a combined passageway between the outlets of the first and second conduits and the exit opening of the housing, having sealing means at one end adapted to close the outlet of the first conduit, and having at its other end a portion cooperating with the cylinder to close the combined passageway; means to bias the piston and its sealing means against the outlet of the first conduit to seal the first conduit and simultaneously block the combined passageway formed by the piston and cylinder, the outlet of the second conduit being open to the cylinder when the piston is biased against the outlet of the first conduit; first connecting means at the entrance opening of the housing to connect the first conduit of the fluid nozzle with a source of a first fluid under pressure, and second connecting means at the entrance end of the housing to connect the second conduit with a source of a second fluid under pressure, whereby supply of the second fluid under pressure through the outlet of the second conduit moves the piston within the cylinder, opening the outlet of the first conduit and opening the combined passageway so that the first fluid is free to mix with the second fluid and to pass through the exit opening of the housing.
 2. A fluid valve and mixing assembly according to claim 1 wherein the cylinder is formed by a sleeve in the central chamber for guiding the piston.
 3. A fluid valve and mixing assembly according to claim 2 wherein the sleeve has a port on the end away from the fluid nozzle and the piston has a portion of its periphery of lesser dimension than the sleeve to form with the sleeve the combined passageway whereby movement of the piston away from the fluid nozzle opens the port to permit the mixture of fluids to pass therethrough around the piston.
 4. A fluid valve and mixing assembly according to claim 3 wherein the sleeve is cylindrical and has a plurality of ports and the piston has a portion having a plurality of flat sides to form the combined passageway with a plurality of passageways.
 5. A fluid valve and mixing assembly according to claim 1 wherein the inlet of the fluid nozzle and the entrance end of the housing are adapted for connection to concentric inside and outside conduits attached to the valve housing at the entrance end, the inlet of the fluid nozzle retaining the inside conduit and the outside conduit being connected to the entrance end to supply a second fluid for passage around the fluid nozzle.
 6. A fluid valve and mixing assembly according to claim 1 wherein the fluid nozzle includes a portion at the outlet of the second conduit having a plurality of webs extending outwardly therefrom, the webs defining with the fluid nozzle and the housing, a plurality of outlets to permit said second fluid to flow past the fluid nozzle.
 7. A fluid valve and mixing assembly comprising a valve housing having a central chamber with an entrance end and an exit end, a fluid nozzle mounted in the central chamber having an inlet end and an outlet end, a first inner conduit adapted to be connected to the fluid nozzle inlet end for supplying a first fluid under pressure to the outlet end of the fluid nozzle, a sleeve mounted in the chamber beyond the fluid nozzle, the sleeve having a pluralIty of ports in the end away from the nozzle, a piston mounted in the sleeve and movable lengthwise thereof, sealing means mounted at one end of the piston, spring means biasing the piston against the outlet end of the fluid nozzle so that the seal means normally closes the outlet end of the fluid nozzle, a second outer conduit concentric with the first conduit and adapted to be connected to the housing entrance end for supplying a second fluid under pressure to the central chamber, a fluid outlet formed between the fluid nozzle and the sleeve to permit the second fluid to initially pass into the central chamber past the fluid nozzle, and a second fluid passageway formed by the outside of the piston and the sleeve which is normally closed but which is opened when the piston is moved away from the fluid nozzle by the flow of the second fluid, the movement of said piston away from the fluid nozzle also permitting the first fluid to exit from the fluid nozzle and mix with the second fluid whereby the mixture of the fluids passes through the second passageway and is discharged through the exit end of the housing.
 8. A fluid valve and mixing assembly according to claim 7 wherein the sleeve has a port on the end away from the fluid nozzle and the piston has a portion of its periphery of lesser dimension than the sleeve which forms part of the second fluid passageway whereby movement of the piston away from the fluid nozzle opens the port to permit the mixture of fluids to pass therethrough around the end of the piston.
 9. A fluid valve and mixing assembly according to claim 7 wherein the housing has a first section and a second section connected together, the end of the second section abutting against at least a portion of the sleeve to retain the sleeve in position in the central chamber. 